Novel U-slot and V-slot DGSs for bandstop filter with improved Q factor

• Published in: IEEE transactions on microwave theory and techniques Vol. 54; no. 6; pp. 2840 - 2847
• Main Authors: WOO, Duk-Jae, LEE, Taek-Kyung, LEE, Jae-Wook, PYO, Cheol-Sig, CHOI, Won-Kyu
• Format: Journal Article Conference Proceeding
• Language: English
• Published: New York, NY IEEE 01-06-2006; Institute of Electrical and Electronics Engineers; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Applied sciences; Banded structure; Bandstop filters; Circuit properties; Electric, optical and optoelectronic circuits; Electronic circuits; Electronics; Exact sciences and technology; Frequency; Frequency filters; Grounds; Metamaterials; Microstrip filters; Microstrip lines; Microwave circuits, microwave integrated circuits, microwave transmission lines, submillimeter wave circuits; Microwave filters; Microwaves; Periodic structures; Photonic band gap; Power harmonic filters; Q factors; Rejection; Resonance; Shape; Spirals; U-slot defected group structure (DGS); V-slot DGS; Vanadium; High Q factor; Q factor; U shape; Microwave; Group structure; Microwave filter; Q band; Periodic structure; Microstrip line; Millimetric wave; Transmission line; Band rejection filter; Band stop filter; U-slot defected group structure (DGS) V-slot DGS; Cascade connection
• ISSN: 0018-9480; 1557-9670
• DOI: 10.1109/TMTT.2006.875450

Novel slot-shaped defected ground structures (DGSs) on the microstrip line are presented to provide a band-rejection property with an improved Q factor. Two different geometries (U-slot and V-slot) are investigated. U-slot and V-slot DGSs have simple shapes compared to the conventional DGSs, however, they provide more steep rejection characteristics. The Q factor of the band-rejection property for the U-slot DGS increases when the distance between two slots in the U-shape decreases. Similarly, the V-slot DGS provides a higher Q characteristic when the slot angle is reduced. Two bandstop filters are designed and fabricated employing three cascaded U-slot DGSs and V-slot DGSs, respectively. Experimental result shows that the high-Q band-rejection filter with three U-slot DGSs provides Q of 38.6. A fabricated filter with three cascaded V-slot DGSs also rejects the signals at the frequencies from 3.5 to 4.3 GHz with more than 20-dB suppression